Activated alumina, also known as aluminum oxide (Al2O3), is a porous solid utilized primarily for adsorption and catalytic applications. It plays a critical role in the adsorption processes involved in the production of hydrogen peroxide, as well as serving as a selective adsorbent for various chemicals, including arsenic and fluoride, during sulfur removal in fluid streams. The Claus catalyst process, which is integral to polyethylene production, utilizes activated alumina for these purposes.